import { List, message, Avatar, Spin } from 'antd'

import reqwest from 'reqwest'

import WindowScroller from 'react-virtualized/dist/commonjs/WindowScroller'
import AutoSizer from 'react-virtualized/dist/commonjs/AutoSizer'
import VList from 'react-virtualized/dist/commonjs/List'
import InfiniteLoader from 'react-virtualized/dist/commonjs/InfiniteLoader'

const fakeDataUrl = 'https://randomuser.me/api/?results=5&inc=name,gender,email,nat&noinfo'

const loadingStyle = {
  position: 'absolute',
  bottom: '-40px',
  left: '30%',
}

class VirtualizedExample extends React.Component {
  state = {
    data: [],
    loading: false,
  }

  loadedRowsMap = {}

  componentDidMount() {
    this.fetchData(res => {
      this.setState({
        data: res.results,
      })
    })
  }

  fetchData = callback => {
    reqwest({
      url: fakeDataUrl,
      type: 'json',
      method: 'get',
      contentType: 'application/json',
      success: res => {
        callback(res)
      },
    })
  }

  handleInfiniteOnLoad = ({ startIndex, stopIndex }) => {
    let { data } = this.state
    this.setState({
      loading: true,
    })
    for (let i = startIndex; i <= stopIndex; i++) {
      // 1 means loading
      this.loadedRowsMap[i] = 1
    }
    if (data.length > 19) {
      message.warning('Virtualized List loaded all')
      this.setState({
        loading: false,
      })
      return
    }
    this.fetchData(res => {
      data = data.concat(res.results)
      this.setState({
        data,
        loading: false,
      })
    })
  }

  isRowLoaded = ({ index }) => !!this.loadedRowsMap[index]

  renderItem = ({ index, key, style }) => {
    const { data } = this.state
    const item = data[index]
    return (
      <List.Item key={key} style={style}>
        <List.Item.Meta
          avatar={<Avatar src="https://zos.alipayobjects.com/rmsportal/ODTLcjxAfvqbxHnVXCYX.png" />}
          title={<a href="https://ant.design">{item.name.last}</a>}
          description={item.email}
        />
        <div>Content</div>
      </List.Item>
    )
  }

  render() {
    const { data } = this.state
    const vlist = ({ height, isScrolling, onChildScroll, scrollTop, onRowsRendered, width }) => (
      <VList
        autoHeight
        height={height}
        isScrolling={isScrolling}
        onScroll={onChildScroll}
        overscanRowCount={2}
        rowCount={data.length}
        rowHeight={73}
        rowRenderer={this.renderItem}
        onRowsRendered={onRowsRendered}
        scrollTop={scrollTop}
        width={width}
      />
    )
    const autoSize = ({ height, isScrolling, onChildScroll, scrollTop, onRowsRendered }) => (
      <AutoSizer disableHeight>
        {({ width }) =>
          vlist({
            height,
            isScrolling,
            onChildScroll,
            scrollTop,
            onRowsRendered,
            width,
          })
        }
      </AutoSizer>
    )
    const infiniteLoader = ({ height, isScrolling, onChildScroll, scrollTop }) => (
      <InfiniteLoader isRowLoaded={this.isRowLoaded} loadMoreRows={this.handleInfiniteOnLoad} rowCount={data.length}>
        {({ onRowsRendered }) =>
          autoSize({
            height,
            isScrolling,
            onChildScroll,
            scrollTop,
            onRowsRendered,
          })
        }
      </InfiniteLoader>
    )
    return (
      <List>
        {data.length > 0 && <WindowScroller>{infiniteLoader}</WindowScroller>}
        {this.state.loading && <Spin style={loadingStyle} />}
      </List>
    )
  }
}

export default VirtualizedExample
